JP3710191B2 - Power transistor drive circuit with single power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transistor drive circuit, and more particularly to a power transistor drive circuit in a single power source that controls a power transistor that drives a specific load so as not to be turned on simultaneously.
[0002]
[Prior art]
Hereinafter, a conventional motor drive circuit in a single power source will be described with reference to the accompanying drawings.
FIG. 4 is a detailed circuit diagram showing a motor driving circuit in a conventional single power source using a relay. As shown in FIG. 4, the motor drive circuit in the conventional single power source is composed of a first relay Rax, a second relay Rbx, and NPN transistors (Q1, Q2).
[0003]
In the first relay Rax, the second terminal a ′ and one terminal of the iron core coil are connected to the plus terminal of the DC single power source Vdc, and the first terminal a is connected to the ground terminal. In the second relay Rbx, the second terminal b ′ and one terminal of the iron core coil are connected to the plus terminal of the DC single power source Vdc, and the first terminal b is connected to the ground terminal. Transistors (Q1, Q2) have collector terminals connected to the other terminals of the core coils of the first and second relays (Rax, Rbx), emitters connected to a common ground terminal, and complementary transistor drive to the base. Input signals (sgn1, sgn2).
[0004]
In such a motor drive circuit, the motor M is connected between the output terminals (ao, bo) of the first and second relays (Rax, Rbx) and driven by these relays. Here, the first terminal (a or b) of the relay (Rax or Rbx) is a terminal connected to the output terminal (ao or bo) when the relay does not operate, and the second terminal (a ′ or b ′) is This terminal is connected to the output terminal (ao or bo) when the relay operates.
[0005]
The conventional motor drive circuit in a single power supply uses two relays (Rax or Rbx) in this way in order to change the rotation direction of the motor M to both directions. That is, by using the relays (Rax, Rbx) for reversing the polarity of the power source Vdc connected to the motor M and changing the polarity of the power source connected to the motor M according to the connection state of the relay, the rotation direction of the motor M Had to be reversed.
[0006]
[Problems to be solved by the invention]
However, in such a motor drive circuit in a single power source using a conventional relay, there is a problem that when the number of times of use of the relay increases, an arc is generated at the relay contact, and the number of times of use is limited. In addition, there is a problem that noise is generated at the contact point due to relay operation.
[0007]
The present invention solves such problems of the prior art, and uses a power transistor as a switching element instead of a relay, thereby changing the polarity of the power supply, thereby driving a power transistor in a single power supply that drives a specific load such as an electric motor. An object is to provide a circuit.
[0008]
For example, Japanese Patent Application Laid-Open No. 7-46886 discloses a motor drive circuit using a power transistor, but the configuration of the drive circuit shown in this document is completely different from the configuration of the present application.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention has an anode connected to a positive terminal of a single DC power source and allows only a positive current to pass through, a transistor control signal is input to the base, and an emitter terminal is connected to the ground terminal A first transistor that controls the flow of a positive current by being turned on / off by a transistor control signal; a base terminal connected to a collector terminal of the first transistor; an emitter terminal connected to a ground terminal; A base terminal is connected to the collector terminal of the second transistor and the emitter terminal is connected to the cathode of the diode, and the second transistor is turned on / off. One terminal is connected to the third transistor that is turned on / off in response to the cathode of the diode, and the first transistor is connected. Star charges the current delivered by the diode when turned on, and a capacitor to discharge the current charged when the first transistor is turned off. In this drive circuit, a first drive signal for driving a transistor output from a first drive terminal connected to an emitter terminal of a third transistor, and a second drive terminal connected to a collector terminal of the first transistor. The second drive signal for driving the output transistor is alternately output.
[0010]
Further, according to the present invention, the power transistor drive circuit configuration in a single power supply includes a diode having a positive electrode connected to a positive terminal of a DC single power supply and passing only a positive current; a transistor control signal as a base input A first transistor having an emitter terminal connected to the ground terminal and controlling a positive current flow by being turned on / off through an input signal; a current connected to a cathode of the diode and a collector terminal of the first transistor; A first resistor for transmitting current; a second resistor for transmitting current by connecting one terminal to the collector terminal of the first transistor; and for transmitting current by connecting one terminal to the other terminal of the second resistor. A third resistor; a current transmitted through the third resistor with the base terminal connected to the other terminal of the third resistor and the emitter terminal connected to the ground terminal Accordingly, the second transistor that is turned on / off; one terminal connected to the collector terminal of the second transistor, and a fourth resistor that transmits the current generated through the second transistor; and the base of the other terminal of the fourth resistor A third transistor having a terminal connected and turned on / off in response to a signal transmitted through the fourth resistor; one terminal connected to the cathode of the diode and transmitted by the diode when the first transistor is turned on; A capacitor for charging the current and discharging the charged current when the first transistor is turned off; a fifth resistor connected to the cathode of the diode and the emitter terminal of the third transistor for transmitting the current discharged from the capacitor; A capacitor connected to the other terminal of the capacitor and the collector terminal of the third transistor; And a sixth resistor for transmitting et discharge current.
[0011]
A power supply unit for supplying a stable power source for driving the entire circuit; a power transistor supplied with the power source and a gate drive signal supplied from the power supply unit, and a power transistor driven according to the input gate drive signal; A load driving unit for driving the electric motor in the forward direction and the reverse direction by the power transistor; in driving the power transistor of the load driving unit, the power supply unit and a transistor control signal are input to turn on / off the internal transistor A first power transistor drive circuit for generating upper and lower gate drive signals so that the first upper and lower power transistors are not turned on simultaneously through the off control; and configured in the same manner as the first power transistor drive circuit; A second upper and lower power transistor through transistor on / off control. Star is so as not to be turned on at the same time, each having an upper and a second power transistor driving circuit for generating a lower gate drive signal.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a power transistor driving circuit in a single power source according to the present invention will be described in detail with reference to the accompanying drawings.
[0013]
(Embodiment 1)
FIG. 1 is a detailed circuit diagram showing a first embodiment of a MOS transistor driving circuit in a single power source according to the present invention.
The MOS transistor drive circuit 20 in the single power source shown in FIG. 1 receives the DC single power source Vdc and the transistor control signal CLK, and performs drive control for alternately turning on the MOS transistors M1 and M2 connected to the output terminals. It is a circuit to perform. The transistor drive circuit 20 includes a diode D1, NPN transistors TR1 and TR2, a PNP transistor TR3, resistors R1 to R6, and a capacitor C1.
[0014]
The diode D1 is a diode having an anode connected to the positive terminal of the DC single power source Vdc and allowing only a positive current to pass therethrough. The first transistor TR1 has a transistor control signal CLK input to the base and an emitter terminal connected to the ground. The transistor TR1 controls the flow of positive current by turning on / off at a predetermined timing by the input CLK signal. The first resistor R1 is connected to the cathode of the diode D1 and the collector terminal of the first transistor TR1, and transmits a current therebetween. The second resistor R2 also has one terminal connected to the collector terminal of the first transistor TR1.
[0015]
The third resistor R3 transmits a current by connecting one terminal to the other terminal of the second resistor R2. The second transistor TR2 has a base terminal connected to the other terminal of the third resistor R3, and an emitter terminal connected to the ground terminal. With this connection, the transistor TR2 is turned on / off by the current transmitted through the third resistor R3. The fourth resistor R4 has one terminal connected to the collector terminal of the second transistor TR2, and transmits a current generated through the second transistor TR2.
[0016]
The third transistor TR3 has a base terminal connected to the other terminal of the fourth resistor R4, and is turned on / off according to a signal transmitted through the fourth resistor R4. The capacitor C1 has one terminal connected to the cathode of the diode D1, and charges the current transmitted by the diode D1 when the first transistor TR1 is turned on, and the charged current when the first transistor TR1 is turned off. Discharge.
[0017]
The fifth resistor R5 is connected to the cathode of the diode D1 and the emitter terminal of the third transistor TR3, and transmits the current discharged from the capacitor C1. The sixth resistor R6 is connected to the other terminal of the capacitor C1 and the collector terminal of the third transistor TR3, and transmits the current discharged from the capacitor C1.
[0018]
Power MOS transistor M1 has a gate connected to the emitter of transistor TR3, one terminal connected to power supply Vdc, and the other terminal connected to a first terminal of a load and one terminal of power MOS transistor M2. The power MOS transistor M2 has a gate connected to the resistors R2 and R3, and the other terminal connected to the ground terminal. Further, the power MOS transistor M3 has a gate connected to the control line 100 of the drive circuit 50, one terminal connected to the power supply Vdc, and the other terminal connected to the second terminal of the load. The power MOS transistor M4 has a gate connected to the control line 102 of the drive circuit 50, one terminal connected to the third terminal of the load, and the other terminal connected to the ground terminal.
[0019]
The drive circuit 50 is a circuit that alternately turns on the transistors M3 and M4. That is, for example, when the transistor M1 is on, the transistor M4 is on and the transistors M2 and M3 are off. Further, when the transistor M 1 is off, transistors M2 and M3 are turned on, the transistor M4 is turned off. The drive circuit 50 is a circuit having substantially the same function as the drive circuit 20.
[0020]
The operation of the power transistor drive circuit in the single power supply of the first embodiment configured as described above is as follows.
First, as shown in FIG. 1, when the control transistor TR1 is turned off by the transistor control signal CLK, the current I flows into the base terminal of the transistor TR2 through the diode D1 and the resistors (R1, R2, R3). Transistor TR2 is turned on. At this time, since the power supply potential is applied to the MOS transistor M2 at the lower end, it is turned on.
[0021]
When the transistor TR2 is turned on, the transistor TR3 is turned on and the charge charged in the capacitor C1 is discharged through the resistors (R5, TR3, R6). When the voltage at both ends of the capacitor C1 decreases due to the discharge and the voltage at the capacitor C1 falls below a certain voltage, the uppermost MOS transistor M1 is turned off.
At this time, the MOS transistor M3 is turned on and the MOS transistor M4 is turned off by the drive circuit 50. Therefore, when the transistor TR1 is turned off, the current I from the power supply voltage Vdc flows to the load (Load) via the MOS transistor M3 and then flows to the lower MOS transistor M2.
[0022]
Next, when the first transistor TR1 is turned on by the transistor control signal CLK, the lower MOS transistor M2 is turned off. At this time, the transistor TR2 is also turned off. When transistor TR2 is turned off, current I charges capacitor C1 via diode D1. When the capacitor C1 voltage becomes equal to or higher than a certain voltage, the upper MOS transistor M1 is turned on.
[0023]
When the upper MOS transistor M1 is turned on, the current I flows through the upper MOS transistor M1 to the load. At this time, since the MOS transistor M3 is turned off and the MOS transistor M4 is turned on by the drive circuit 50, the current I flows to the MOS transistor M4 via the load.
[0024]
Thus, in this embodiment, since the MOS transistors (M1, M2) are not turned on at the same time, there is no possibility that the elements (M1, M2) are burned out. Similarly, since the MOS transistors (M3, M4) are not turned on at the same time, the elements (M3, M4) are not likely to be burned out.
[0025]
FIG. 2 is a timing chart of the MOS transistor driving circuit in the single power source shown in FIG. As shown in FIG. 2, when the first transistor TR1 is turned from the turn-off state, the upper MOS transistor M1 is turned on, and the lower MOS transistor M2 is turned off.
[0026]
(Embodiment 2)
FIG. 3 is a detailed circuit diagram showing a second embodiment of the motor drive circuit in the single power source according to the present invention.
[0027]
The motor drive circuit in the single power source shown in FIG. 3 includes a power supply unit 10, a load drive unit 30, a first power transistor drive circuit 20, and a second power transistor 21.
[0028]
The power supply unit 10 is a power supply circuit that supplies a stable power supply for driving the entire circuit. The load drive unit 30 is a drive circuit that inputs a power supply and a gate drive signal supplied from the power supply unit 10 and drives a load.
[0029]
The load drive circuit 30 includes N-channel power MOS transistors (M1 to M4) that are driven according to an input gate drive signal, and an electric motor 31 that is driven in the forward and reverse directions by the power transistor.
[0030]
The first power transistor drive circuit 20 is supplied with power from the power supply unit 10 and receives a transistor control signal CLK1, so that the first upper and lower MOS transistors (M1, M2) are not turned on simultaneously. This is a circuit for generating gate drive signals for the upper and lower transistors (M1, M2). That is, the drive circuit 20 includes a transistor therein, and when the MOS transistor (M1, M2) of the load drive unit 30 is driven, the power supply unit 10 and the transistor control signal CLK1 are input to turn on the internal transistor. / Off control.
[0031]
The second power transistor drive circuit 21 is configured in the same way as the first power transistor drive circuit 20 so that the second upper and lower MOS transistors (M3, M4) are not turned on simultaneously through on / off control of the internal transistors. The upper and lower gate drive signals are generated.
[0032]
The power supply unit 10 includes a diode Ds, a resistor Rs, a Zener diode ZD1, a capacitor Cs, and a transistor TR7. The diode Ds is a diode that supplies a positive current with an anode connected to the plus terminal of the DC single power source Vdc. The resistor Rs has one terminal connected to the anode of the diode Ds and transmits a current. Zener diode ZD1 is connected to the other terminal of resistor Rs and the ground terminal, and allows only a constant voltage to pass therethrough.
[0033]
The capacitor Cs is connected in parallel with the Zener diode ZD1 to charge and discharge the voltage supplied by the Zener diode ZD1. The transistor TR7 has a base terminal connected to one terminal of the capacitor Cs and a collector terminal connected to the cathode of the diode Ds. The transistor TR7 is turned on / off by the voltage of the capacitor Cs, and supplies a current generated when the transistor TR7 is turned on as a current source of the first and second power transistor drive circuits (20, 21).
[0034]
The load driving unit 30 includes two upper power transistors (M1, M3) and two lower power transistors (M2, M4). The upper power transistors (M1, M3) input the power supplied from the power supply unit 10 to a common drain terminal, and respectively supply the gate drive signals of the first and second power transistor drive circuits (20, 21) to the gate terminals. To be driven.
[0035]
The lower power transistors (M2, M4) have a drain terminal connected to the source terminals of the upper power transistors (M1, M3), a common source terminal connected to the ground terminal, and first and second power transistor drive circuits. The gate drive signals (20, 21) are respectively input to the gate terminals.
[0036]
An electric motor (Motor) is connected to the load driving unit 30. The electric motor is driven in the forward direction or the reverse direction (Rot1, Rot2) by switching of these four power transistors (M1, M2, M3, M4).
[0037]
Next, the operation of the motor drive circuit in the single power source of the third embodiment shown in FIG. 3 is as follows.
First, as shown in FIG. 3, the upper and lower MOS transistors (M1) of the load drive unit 30 are connected to the base terminals of the control transistors (TR1, TR4) of the first and second power transistor drive circuits (20, 21). , M2, M3 and M4) are applied with transistor control signals (CLK1, CLK2) so that they are not turned on simultaneously.
[0038]
When the electric motor (Motor) of the load driving unit 30 is not driven, the control transistors (TR1, TR4) hold the turn-off state. When the transistors (TR1, TR4) are turned off, the values of the resistors (R1, R2, R3 and R10, R11, R12) are determined so that the transistors (TR2, TR5) can be turned on.
[0039]
When the transistors (TR2, TR5) are turned on, the transistors (TR3, TR6) are turned on, and the upper MOS transistors (M1, M3) of the load driving unit 30 hold the turn-off state, and the lower MOS transistors (M2, M4) ) Is turned on and the motor is not driven.
[0040]
As shown in FIG. 3, if the rotation direction of the motor when the MOS transistors (M1, M4) are turned on and the MOS transistors (M2, M3) are turned off is defined as “Rot1”, the motor is defined as “Rot1”. In order to rotate in the direction, the control transistor TR1 of the first power transistor drive circuit 20 is turned on.
[0041]
When the first transistor TR1 is turned on, the lower MOS transistor M2 and the transistor TR2 are turned off. When the transistor TR2 is turned off, the transistor TR3 is turned off, so that the current I charges the capacitor C1 through the transistor TR7 of the power supply unit 10 and the diode D1 of the first power transistor driving circuit.
[0042]
When the voltage of the capacitor C1 exceeds a certain voltage, the upper MOS transistor M1 is turned on. At this time, since the lower MOS transistor M2 has already been turned off, it does not occur when the upper and lower MOS transistors (M1, M2) are turned on simultaneously.
[0043]
Conversely, when the rotation direction of the motor is “Rot 2”, the polarity of the power source connected to the motor 31 is reversed by turning on the MOS transistors (M2, M3) and turning off the MOS transistors (M1, M4). The direction of rotation changes.
[0044]
Here, in order to turn on the MOS transistors (M2, M3) and turn off the MOS transistors (M1, M4), the transistor TR4 of the second power transistor drive circuit 21 is turned on. When the transistor TR4 is turned on, the transistors (TR5, TR6) are turned off, and the current I is charged through the transistor TR7 of the power supply unit 10 and the diode D3 of the second power transistor drive circuit 21.
[0045]
When the capacitor C2 voltage becomes equal to or higher than a certain voltage, the MOS transistor M3 is turned on. At this time, since the MOS transistor M4 is already turned off, the two transistors are not turned on simultaneously.
[0046]
Therefore, since the transistor TR1 is turned off, the MOS transistor M1 is turned off, the MOS transistor M2 is turned on, the MOS transistors (M1, M4) are turned off, the MOS transistors (M2, M3) are turned on, and the rotation direction of the motor is changed. It becomes “Rot2”.
[0047]
The power transistor drive circuit that operates in this way can be applied in various fields such as a drive device for an automobile window motor or a power antenna drive device.
[0048]
【The invention's effect】
As described above in detail, according to the power transistor driving circuit in the single power source of the present invention, when a specific load is driven, a switching element is used instead of a relay. Can be solved, and the problem that the number of uses is limited can be solved. In this case, since the power transistors are not turned on at the same time, each element can be prevented from being burned out. Furthermore, since the relay is not used, it is possible to solve the problem that noise is generated at the contact due to the relay operation.
[Brief description of the drawings]
FIG. 1 is a detailed circuit diagram showing a first embodiment of a MOS transistor drive circuit in a single power supply according to the present invention.
FIG. 2 is a timing chart of a MOS transistor driving circuit in the single power source shown in FIG.
FIG. 3 is a detailed circuit diagram showing a second embodiment of a MOS transistor drive circuit in a single power supply according to the present invention;
FIG. 4 is a detailed circuit diagram showing a motor drive circuit in a conventional single power source.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Power supply part 20 1st power transistor drive circuit 21 2nd power transistor drive circuit 30 Load drive part Motor Electric motor

Claims (7)

A diode whose anode is connected to the positive terminal of a single DC power source and passes only positive current;
A first transistor having a transistor control signal as a base input, an emitter terminal connected to a ground terminal, and being turned on / off through the input signal to control the flow of the positive current;
A first resistor connected to the cathode of the diode and the collector terminal of the first transistor for transmitting current;
A second resistor having one terminal connected to the collector terminal of the first transistor and transmitting a current;
A third resistor that is connected to the other terminal of the second resistor and transmits a current;
The base terminal to the other terminal of the third resistor and the collector terminal of the first transistor is connected transmitted by the emitter terminal connected to the ground terminal through the third resistor in response to said first transistor ON / OFF A second transistor that is turned on / off by a current that is applied;
A fourth resistor having one terminal connected to the collector terminal of the second transistor and transmitting a current generated through the second transistor;
A base terminal is connected to the collector terminal of the second transistor through the fourth resistor , an emitter terminal is connected to the cathode of the diode, and a signal transmitted through the fourth resistor according to on / off of the second transistor. A third transistor which is turned on / off in response;
A capacitor having one terminal connected to a cathode of the diode, charging a current transmitted by the diode when the first transistor is turned on, and discharging a charged current when the first transistor is turned off; ,
A fifth resistor connected to the cathode of the diode and the emitter terminal of the third transistor and transmitting a current discharged from the capacitor;
Which is connected to the collector terminal of the other terminal and the third transistor of the capacitor, it possesses a sixth resistor for transmitting current discharged from the capacitor, and
A first drive signal for driving a transistor output from a first drive terminal connected to the emitter terminal of the third transistor, and a second drive terminal connected to a collector terminal of the first transistor. A drive circuit for a power transistor in a single power supply, wherein a second drive signal for driving the transistor is alternately output . The first, a drive circuit of a power transistor in the single power supply of claim 1, wherein the second transistor is characterized in that it consists of an NPN transistor. 2. The power transistor drive circuit according to claim 1 , wherein the third transistor is a PNP transistor. A power supply unit for supplying a stable power source for driving the entire circuit;
A load drive unit that includes a power transistor that is supplied with power and a gate drive signal supplied from the power supply unit and is driven according to the input gate drive signal, and that drives the electric motor in the forward direction and the reverse direction with the power transistor. When,
When driving the power transistor of the load driving unit, the power supply unit and a transistor control signal are input, and the upper side of the first side and the lower side power transistor are not turned on simultaneously through on / off control of the internal transistors. A first power transistor drive circuit for generating a lower gate drive signal;
The second power source driving circuit is configured in the same manner as the first power transistor driving circuit, and generates upper and lower gate driving signals so that the second upper and lower power transistors are not turned on simultaneously through on / off control of the internal transistors. possess the power transistor drive circuit, the,
The power supply unit
A diode for supplying a positive current with an anode connected to a positive terminal of a single DC power supply;
A resistor having one terminal connected to the anode of the diode and transmitting a current;
A Zener diode that is connected to the other terminal of the resistor and the ground terminal and allows only a constant voltage to pass through;
A capacitor connected in parallel with the Zener diode for charging and discharging a voltage supplied by the Zener diode;
A base terminal is connected to one terminal of the capacitor, a collector terminal is connected to the cathode of the diode, and is turned on / off by a capacitor voltage. Current generated when the capacitor is turned on is supplied to the first and second power transistor drive circuits. And a transistor to be supplied as a current source of the motor. The load driving unit is
Two upper power transistors that are driven by power supplied from the power supply unit being input to a common drain terminal and gate drive signals being respectively input to the gate terminals;
A drain terminal is connected to the source terminal of the upper power transistor, a common source terminal is connected to the ground terminal, and two lower power transistors that are driven by inputting gate drive signals to the gate terminals,
5. The electric motor drive circuit for a single power supply according to claim 4 , further comprising an electric motor connected between the source terminals of the upper power transistor and driven in the forward direction and the reverse direction by the power transistor. 5. The electric motor drive circuit for a single power supply according to claim 4 , wherein the transistor is an npn transistor. 6. The electric motor drive circuit for a single power supply according to claim 5 , wherein the power transistor is an N-channel MOS transistor.

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